A contract that is "void" cannot be enforced by either party., The law treats a void contract as if it had never been formed. A contract will be considered void, for example, when it requires one party to perform an act that is impossible or illegal.
A "voidable" contract, on the other hand, is a valid contract and can be enforced. Usually only one party is bound to the contract terms in a voidable contract. The unbound party is allowed to cancel the contract, which makes the contract void.